Evidence indicates that unresponsive and insensitive care in early infancy is associated with impairments in social and cognitive development. Maternal depression, characterized by sadness, withdrawal, and irritability, appears to interfere with mothering and place young children at developmental risk. Infants of women who are depressed postpartum may be especially vulnerable, since infancy is seen as a crucial time for the development of the mother-infant relationship and the motivation to master the environment. Attachment theory predicts that infants with depressed mothers will be less securely attached and less engaged with the environment. However, no studies have examined the antecedents of attachment or mastery motivation in infants of depressed mothers. We are currently engaged in a longitudinal study to examine the impact of postpartum depression on the developing mother-infant relationship. Middle-class, married, primiparous women who meet Research Diagnostic Criteria for Depression in the postpartum period are matched on demographic variables with non-depressed women. Women and their infants are observed at 2, 4, and 6 months during social interaction. The duration, course, and severity of maternal depression are also assessed. We seek continued funding to follow our sample in order to assess mastery motivation and quality of attachment at 12 months. We expect the quality of early mother-infant interaction and the severity and duration of maternal depression to predict the quality of the infants attachment to mother, as indexed by behavior in the Strange Situation, and mastery motivation, as indexed by persistence with and interest in novel toys. It also has been assumed that the postpartum period is a time of increased risk for depression and that women with a previous episode of postpartum depression will be more likely to experience another episode after a subsequence pregnancy. We plan to follow our sample through the birth of the second child, in order to examine these issues prospectively. We will also observe the quality of mother-infant interaction with first borns and second borns, using mothers as their own controls, and taking into account concurrent mood and child characteristics. Finally, we will track the course of maternal depression and the adjustment of the first child through toddlerhood and the early preschool years.